CRYSTAL CHEMISTRY AND GENESIS OF ORGANIC MINERALS: A REVIEW OF OXALATE AND POLYCYCLIC AROMATIC HYDROCARBON MINERALS
Bibliographic record
Abstract
Organic minerals are natural organic compounds with both a well-defined chemical composition and crystallographic properties; their occurrences reveal traces of the high concentration of certain organic compounds in natural environments. Thus the origin and process of formation of organic minerals will lead us to understand the fate and behavior of the organic molecules in the lithosphere. With the aim of their contribution to new developments in mineralogy, we subdivide organic minerals into two groups: (1) ionic organic minerals, in which organic anions and various cations are held together by ionic bonds, and (2) molecular organic minerals, in which electroneutral organic molecules are bonded by weak intermolecular interactions. This review is composed of four sections. The first section is concerned with the definition of both organic minerals and the above two groups. The second deals with crystal chemistry and geochemistry of oxalate minerals, which are the most typical ionic organic minerals. In this section, the role of (H 2 O) 0 is first discussed, as most oxalate minerals incorporate (H 2 O) 0 into their crystal structures. Then the phase relationships among hydrous and anhydrous calcium oxalate minerals, namely their structural hierarchy, are described, owing to the fact that they are the most abundant ionic organic minerals. In addition, the weak Jahn– Teller effect of the Fe 2+ ion is exemplified in humboldtine [Fe 2+ (C 2 O 4 )·2H 2 O]. The Fe 2+ ion causes distortions of octahedra in this organic mineral, though the effect has hardly been observed in inorganic minerals. In the third section, we describe the crystal chemistry and process of formation of polycyclic aromatic hydrocarbon (PAH) minerals, which are the most typical molecular organic minerals. Those of karpatite (C 24 H 12 ) and idrialite (C 22 H 14 ) are particularly considered in detail. In the fourth section, we summarize the characteristics of organic minerals and discuss their contribution to Earth and planetary sciences.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".